blue bar blink on vaadin 7 sometimes


I have an application who developper with Vaadin 7 and when I charge pages of application or when i click on a button in my application, sometimes, i have a blue bar on the top of my application who blinks indefinitely and i can wait 10 minutes the blue bar continue to blinks.
Often, the blue bar doesn’t blink and disappear in two or three seconds.

Do you have idea why sometimes my blue bar blink ?

Best regard

The blue loading indicator means that the application is waiting for a response from the server. When you do some action like clicking a button, a request is sent from the browser to the server. The server starts executing the code that is listening to this click action. In the case of a button, it’s the ClickListener of the Button. Once the listener has completed, a response is sent back to the browser. When all of this is happening, the blue loading indicator will be showing. If you are, for example, invoking a slow database operation from the click listener, it could take a long time.

Ok you think the problem can be my database is slowly ?
Because often the blue loading indicator is fast but there is sometimes, the blue loading is blocked and it blinks and i can wait many times, the blue loading doesn’t disappear never. I must to refresh my page to deblock situation

It’s possible that it’s your database, but it could easily be something else as well.

Do you have another idea for something else ?

Any access to an external system can be slow, but it could be a slow loop, too. If you can reproduce the issue, a Java Profiler could be helpful: